Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Fix race of snd_seq_timer_open() The timer instance per queue is exclusive, and snd_seq_timer_open() should have managed the concurrent accesses. It looks as if it's checking the already existing timer instance at the beginning, but it's not right, because there is no protection, hence any later concurrent call of snd_seq_timer_open() may override the timer instance easily. This may result in UAF, as the leftover timer instance can keep running while the queue itself gets closed, as spotted by syzkaller recently. For avoiding the race, add a proper check at the assignment of tmr->timeri again, and return -EBUSY if it's been already registered.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux Kernel | < 5.10.44 |
Related Weaknesses (CWE)
References
- https://git.kernel.org/stable/c/536a7646c00a0f14fee49e5e313109e5da2f6031Patch
- https://git.kernel.org/stable/c/83e197a8414c0ba545e7e3916ce05f836f349273Patch
- https://git.kernel.org/stable/c/bd7d88b0874f82f7b29d1a53e574cedaf23166baPatch
- https://git.kernel.org/stable/c/536a7646c00a0f14fee49e5e313109e5da2f6031Patch
- https://git.kernel.org/stable/c/83e197a8414c0ba545e7e3916ce05f836f349273Patch
- https://git.kernel.org/stable/c/bd7d88b0874f82f7b29d1a53e574cedaf23166baPatch
FAQ
What is CVE-2021-47281?
CVE-2021-47281 is a vulnerability with a CVSS score of 7.0 (HIGH). In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Fix race of snd_seq_timer_open() The timer instance per queue is exclusive, and snd_seq_timer_open() should have manage...
How severe is CVE-2021-47281?
CVE-2021-47281 has been rated HIGH with a CVSS base score of 7.0/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-47281?
Check the references section above for vendor advisories and patch information. Affected products include: Linux Linux Kernel.